A136952 - OEIS

%I #9 Apr 12 2024 09:51:27

%S 0,7,70,97,700,970,997,7000,9700,9747,9970,9997,70000,70997,75997,

%T 97000,97470,99700,99970,99997,700000,709970,709997,759970,759997,

%U 970000,974700,997000,999700,999970,999997,7000000,7050497,7099700,7099970,7099997,7450497,7599700,7599970,7599997,9700000,9747000,9970000,9979757,9997000

%N Numbers k such that k and k^2 use only the digits 0, 4, 5, 7 and 9.

%C Generated with DrScheme.

%H Jonathan Wellons, <a href="/A136952/b136952.txt">Table of n, a(n) for n = 1..599</a>

%H J. Wellons, <a href="https://web.archive.org/web/20090206165028/http://jonathanwellons.com/shared-digits/">Tables of Shared Digits</a> [archived]

%e 707075495050497^2 = 499955755700905407544579947009.

%t With[{c={0,4,5,7,9}},Select[FromDigits/@Tuples[c,7],SubsetQ[ c,IntegerDigits[ #^2]]&]] (* _Harvey P. Dale_, Nov 19 2019 *)

%K base,nonn

%O 1,2

%A Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008